Refractory gun



Mrfch 5, 929,

' G. P. MCB/IANAMNA REFRACTORY GUN Filed Feb. 8, 1928.

Patented Mar. 5, H92@ UNH@ STATES retenir ernten GERALD P. MUMNAMNA, OFPORTLAND, OREGON, ASSIGNOR TO MCCRN-REPLEY C0., OF PORTLAND, OREGON, ACORORATON OF OREGON.

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Application led February 8, 1928. Serial No. 252,806.

My invention relates especially to. the socalled refractory guns havingfor lts purpose the spraying of a plastic material upon the walls of acombustion chamber, for relining the same and restoring them to functionproperly after having been worn away in service.

My invention incidentally relates to devices employed for coating anywall surface with a cementitious material.

The average boiler or industrial furnace burns out the re brick liningat the rate of one-fourth to one-half an inch a month, in the heavy dutyzones or parts of the furnace where the greatest wear takes place; andsome furnaces will double this average wear.

The re-surfacing of the re brick lining when done by hand is a slowprocess, and so there has, heretofore, been devised a socalledrefractory gun which was employed for applying the spray or coating ofthe plastic material to restore the burnt away wall surfaces; and suchrefractory guns d-o the work better than can be done by hand.

But these devices, as known to me, do not work satisfactorily norefficiently, because it is necessary to make the plastic mixture with anexcess of water, in order to render it thin enough for use in saidrefractory guns.

In other words, the plastic material, if'

made of the proper consistency was too heavy or stiff to be forcedthrough thelllmited outlet in the gun by the employmentof air underpressure, or secondary air,` blast as such pressure 1s commonly referred"to In order to overcome such resultan render the plastic mixture usable'for' the,

refractory gun it was, therefore, necessary to intermix therewith anexcess ofwaterto;

render the composition thin enough toipermit it being forced through therrestricted outlet of the refractory gun. But-when so doing thefollowing difhculties were created:

The excess Water materially weakened the bonding strength ofthe hightemperature cement, causing it to separate and fall o'. Obviously, apatchthat will not stick is no repair at all.

jThis excess water has to be evaporated out pf the patch, which causesexcessive and refractory material will not build or objectionableshrinkage developing large cracks in .the patch after the furnace hasbeen fired.

Due to the excess water, the sprayed on ile up on the wall, much over aquarter o an inch at a time, being so wet it runs down the wall or dropsoff entirely, which slows up the operation, as it is necessary to waitconsiderable time after each application for the material to drysufficiently to take the next coat; and it will be readily seen this isa serious objection for the time element is paramount in such work.

Restoration of furnace walls sometimes necessitates rebuilding to adepth of three or four inches, and to wait for each coat of one quarterto three eighths of an inch to dry means considerable loss of time, inaddition to the time required to dry out the vast amount of excesswater.

Further, the time required in emptying the gunis too long to beeconomical of even the labor required, not to mention the loss due tothe time the plant is out of use.

Theobject of my invention is to provide a refractory gun, adapted tospray plastic material of the proper consistency without clogging orcreating, air ockets within itself while it is discharging which wouldtend to prevent the mixture from dowing Eninterruptedly through thedischarge ori- A further object of my invention is to provide arefractory gun of simple construction and which will operate in anecient manner.

I' attain my object, in agun of the character described comprising thecombination of a container provided with a head constituting a surgechamber, said head having converging walls terminating in a tubularelongate projection chamber arranged transverse of the axis of thecontainer, the surge chamber and the projection chamber being connectedby an elongate opening in combination with means for elevating theplactic material in the container into the said head, and means forapplying Huid pressure to project the material from the said projectionchamber. A

Further details of my invention and the construction and operationthereof are hereinafter fully described with reference to theaccompanying drawings, in which? Fig. 1 shows a side elevation of myinvention partly in section andillustrates the details of constructionthereof.

Fig. 2 shows a longitudinal, sectional perspective View of the containerand head and illustrates the proportions ofthe projection chamber. l

Fig. 3 shows a fragmentary, section of the removable headtakenlongitudinally through the projection chamber and illustratesdiagrammatically the movement of the plastic material and the action ofthe secondary airu blast. i

Figaft shows in a fragmentary, transverse section a modification in theform of the projection chamber. 3

With reference to the figures my refractory gun comprises a cylindricalcontainer a provided with a removable hea-d b, circular at its base, butthe walls converging ,up- Wardly, forming a Wedge-shaped surge chamberterminating in an elongate cylindrical projection chamber c transverseof the vertical axis of the container.

APorts are provided at each end of the said rojection chamber, formingrespectively, an inlet orifice d, connected with'a fiuid pressure linee, which provides the secondary air blast, and a discharge orifice fconnected to a suitable hose, g, provided at its endwith a nozzle la.through which the plastic material from the container is discharged.

A filling door z' is rovided in one of the sidewalls of Athe heaprovided with offset flanges i ,in order that the said door may beseated Hush with the interior surface of the Wall and at the same timeprovide a fluid tight closure without obstructions on its ina pressureline Z in which are terior surface to' the movement of the materialthrough the head.

A free moving piston j is provided in the container a and an orifice kis provided in the bottom of the container, connected with rovidedshutofi valves m and n, and an Q: aust valve o',

f arranged between them, the exhaust valve serving to release thepressure under the piston and permit it to return to the bottom of thecontainer, by gravity.

The pressure lines e and Z are connected by a T p to the main pressureline g. A shut-oil valve 1' is also provided in the pressure line c anda pressure gauge s is connected to the pressure line e on the intakeside of the valve r.

In the operation of my refractory gun, the valves m, n and fr beingclosed and the fluid pressure shut off, the plastic, integrally mixedmaterial isloaded into the container through the door 'i and`-`f1led upto the base of the head b, the bottom of the contamer.

piston g resting on the The container being loaded and the door z"ktightly closed and the work ready to be started, the valves m, m. and 7'are opened, the exhaust valve o bein already closed, and fluid pressureis permitted to enter the container, beneath the piston g, forcing itup- .Ward and the plastic material intothe head b, and the secondary'air blast entering the projection chamber through the orifice 0l, blowsthe lplastic material out through the orifice f, the hose g and nozzleIt, as a spray onto the surface being coated.

When the plastic material is all discharged from the gun which will bein approximately two minutes, the valves m, n and 1 are shut off and theexhaust valve la is opened which permits the pressure in the containerto escape andthe piston to return by gravity to the bottom of thecontainer.

To repeat the operation, the container will again be filled, the exhaustvalve closed, and the Valves m, n. and 1' opened and the work of lininga furnace wall with refractory material may go on.

Thus it maybe plainly seen that in the work of lining'the furnace wallsof industrial plants, in which the time element is of im ortance, willbe carried on rapidly and e ciently, with only the .necessary inpterruption f or filling the container. Also, by providing the head orsurge chamber b of the container with converging walls and an elongate,cylindrical projection chamber, the plastic material being forced intoit by the upward pressure of the 100 pistonj, will not be retarded byany 'obstruc- `tionson the said walls and further by conwhich wouldresult in the material not being delivered through the outlet orificecontinuously, causing the flow therefrom to be uneven and contain moremoisture sometimes than others.

The tendency of the material to be compressed to ,too great a degree andto squeeze out some of the moisture by the compression of the materialinto a smaller volume is also avoided, the area of the inlet of theprojection chamber being four times as great as the cone shaped head ofthe refractory guns of the type now in general use.

Further by providing an elongate projection chamber With an inletorifice at ono end admitting a secondary air blast and the outletorifice at the other, the plastic inaterial is rapidly picked up as itenters the 123 projectionl chamberand atomized and blown out the outletorifice and through the hose, as illustrated in Fig. 3.

This action is further accelerated by forming the projection chambernearly cylindri- 13o j walls terminating in a-tubul groesse out some ofits moisture content and cause the plastic material to be too dry andstick and clog the projection chamber.

In Fig. 4 is shown a modification of the head b, in which the projectionchamber 3 is not cylindrical, the side walls being parallel, therebyproviding an increased area for the admission 'of the material therein,but at the same time permitting the plastic material to expand slightlyin the increased cross sectional area. Y

A T 5 is provided in the connection of the pressure line to the valve mand a short pipe section 6 is connected thereto, provided with a valve 7and acap j By this means the hose g may beremoved from the outlet orice7 and connected to the pipe section 6, the cap 8 then being screwed overthe orifice f, and a plug 9 provided in the piston j will be removed,the piston being permitted to rest onthe bottom of the container a, thecontainer then being filled with drysan j By closing the valve ot andopeningl the valves m, r and 7, the sand may be blown out through thehose g and my refractory gun used for sand blasting, which is aneiicient method of preparin wall surfaces for receiving a coating of reractory or cementitious material'. l v

1. In a sprayer for plastic material, a container provided with a headconstituting a surge chamber, said'head havingl converging are ongateprojection chamber arran ed transverse of the axis of the container, t esurge chamber and the projection chamber being connected by an elongateopening, in combination. with means for elevating the plastic materialin the container into the said head, and means for applying iiuidpressure tov project the materlal from the said projection chamber.

2. In a sprayer for plastic material a container provided with a headconstituting a surge chamber, said head having converging walls.terminating in a tubular elongate projection chamber arrangedtransverse of the axis of the container, the surge chamber and theprojection chamber being connected by anvelongate opening, the lcrosssectional area of the projection chamber being greater than the width ofsaid opening, in combination with meansfor elevating the plasticmaterial in the container into the said head,

and means for applying Huid pressure to preject the material from thesaid projection chamber. Y

3. In a sprayer for plastic material, a container provided with aheadconstituting a surge chamber, said head having converging wallsterminating in a cylindrical elongate projection chamber arrangedtransverse'of the axis of the container,.the` surge chamber and theprojection chamber being connected by an elongate opening, the diameterof the projection chamber being greater than the width of said opening,in combination with means for elevating the plastic material inthe'container into the said head, and means fory applying fluid ressureto project the material from the sai projection chamber.

4. In a sprayer `for 'plastic material the combination of a containerprovided with a removable head constituting a surge chamber, said headhaving converging walls terminating in a tubular elongate chamberarranged transverse of t e axis of the container, the surge chamber andthe projection chamber bemg connected by an elongate opening and a duidpressure pipe connected to` one end of said projection chamber, theopposite end of the latter being adaptedv to have a delivery pipevattached thereto.

5. In a sprayer for plastic material the combination of a containerprovided with a head constituting a surge chamber, said head havingconverging walls terminating in a tubular elongate projection chamberarranged transverse of the axis of the container, the surge chamber andthe projection chamber being connected by an elongate opening and one ofsaid converging walls provided with a door.

6. Inr` a sprayer for plastic material the combination 'of a containerAprovided with a head constituting a surge chamber, .said head havingconverging walls terminating in a tubular elongate rojection chamberarranged transverse of t e axis of the container, the surge chamber andthe projection chamber being connected by an elongate opening and one ofsaid converging walls' provided with a door whose inner surface is gushwith the interior surface of such wa 7. In a sprayer for plasticmaterial the i combination of a container provided with a headconstituting a surge chamber, said head having converging wallsterminating 1 in a tubular elongate -projection chamber arrangedtransverse of the axis of the container, the surge chamber and theprojection chamber being connected by an elongate opening, afluid-pressure pipe connected to one end of said projection chamber, theopposite end of the glatter being adapted to have a'delivery pi eattached thereto and the cross section o the projection chamber beinggreater than that of said Huid pressure pipe.

